1. Field of the Invention
The present invention relates to a Time Lapse recording and reproducing method for optical disks, and more particularly, to a device and method for recording and reproducing video data on and from an optical disk using a Time Lapse recording/reproduction process.
2. Description of Related Art
Conventional Time Lapse recording devices and methods are generally used in security systems for monitoring and recording activities in security sensitive areas, such as banks or museums. A conventional Time Lapse Video Cassette Recorder (Time Lapse VCR) records and reproduces video signals on and from magnetic tapes.
FIG.1 shows a block diagram of a conventional Time Lapse VCR. As shown therein, the conventional Time Lapse VCR includes an A/D (analog-to-digital) converter 10 for converting an analog image signal input from a camera device, such as a CCD camera, into digital image data; a buffer memory 21 for temporally storing the digital image data therein; a field memory 22 for outputting the digital image data of the buffer memory 21 when the field memory 22 is full; a D/A (digital-to-analog) converter 30 for converting the digital image data output from the field memory 22 into an analog image signal; a recording/reproducing unit 40 for recording the analog image signal on a magnetic tape; an input unit 60 for receiving a user's option or user's selection; and a controller 50 for controlling the read and write operation of the memories 21 and 22 and controlling to store the image data intermittently with a predetermined time interval according to the user input received from the input unit 60.
The controller 50 selects each frame of the image data of the buffer memory 21 with a predetermined time interval which is based on the recording time set by the user's input, and stores each of the frames in the field memory 22. In other words, the controller 50 transfers image data stored in the buffer memory 21 in frame units to the field memory 22. As a result, time-sensitive image data are compressed and stored in the field memory 22 in frame units.
When the field memory 22 is completely full, the controller 50 controls the recording/reproducing unit 40 to begin recording of an analog image signal output from the D/A converter 30. At the same time, the controller 50 continues to store the converted image data in the buffer memory 21. Upon completion of the recording operation, a frame of the image data corresponding to a predetermined time interval is transferred from the buffer memory 21 to the field memory 22 and stored therein. This process is repeated to store an image signal in a Time Lapse manner.
The conventional Time Lapse VCR as described above must forwardly move and stop the tape repeatedly to continuously Time Lapse record the image signal based on the size of the field memory 22. This results in considerable use and wear of the deck and drum of the conventional Time Lapse VCR, so that the drum and deck must be replaced frequently. Furthermore, the magnetic tape on which the image signals are recorded and reproduced deteriorates quickly due to the friction against the heads 2 of the VCR. This affects the quality of image being displayed by the conventional Time Lapse VCR and the life span of the VCR.